High throughput method for wireless multi-hop networks with string topology using directional antennas <Abstract> It is one of the problems for the IEEE 802.11 based multi-hop networks that the throughput decreases because of the hidden-terminal problem. There were some proposals of Medium Access Control (MAC) protocols using directional antennas for avoiding the hidden-terminal problem. However, the systems using the directional antennas yield a new type of hidden terminal problem. This paper presents a novel MAC protocol using multiple directional antennas. The proposed protocol uses multiple directional antennas and transmission control signals generated by transmitters. The simulation results and the maximum throughput analysis are shown. The analytical result denotes that the bottleneck for achieving the highest throughput of the proposed protocol is not a collision effect but a carrier-sensing effect because of the collision reduction. |